1. Technical Field
The present invention relates to a terahertz wave generation device, a light source device, a camera, an imaging device, and a measurement device.
2. Related Art
Terahertz waves have recently gained attention. Terahertz waves are electromagnetic waves having frequencies of equal to or greater than 100 GHz and equal to or less than 30 THz. The terahertz waves, for example, may be used for imaging, respective measurements such as spectroscopic measurements, nondestructive inspection, and the like.
A terahertz wave generation device that generates such a terahertz wave includes a light source device that generates an optical pulse having a pulse width on the order of subpicoseconds (several hundreds of femtoseconds), and an antenna that generates a terahertz wave through irradiation of the optical pulse that is generated from the light source device onto the antenna. As a light source device that generates an optical pulse having a pulse width on the order of subpicoseconds, a femtosecond fiber laser or a titanium sapphire laser is used.
However, if the femtosecond fiber laser or the titanium sapphire laser is used, the device becomes large. In order to miniaturize the device, a method of generating an optical pulse having a target pulse width using an optical pulse generation device that generates an optical pulse having a pulse width that is larger than the target pulse width and a pulse compression device that performs pulse compression with respect to the optical pulse generated by the optical pulse generation device has been adopted.
Such a pulse compression method may use saturable absorbers (for example, see Japanese Patent No. 3328881).
However, according to the method that uses the saturable absorbers, to obtain an optical pulse having a desired pulse width, it is necessary to make the optical pulse pass through plural saturable absorbers, and this causes the length of the light source device to become too long.
Another pulse compression method uses a group velocity dispersion compensation medium (for example, see Japanese Patent No. 3014039).
However, only an optical pulse having a desired pulse width may not be obtained by the method that uses the group velocity dispersion compensation medium.